Cast iron pipes are made of casting cast iron, which are applied to water supply, drainage and gas pipelines. Cast iron pipes include cast iron straight pipes and pipe fittings. The cast iron pipe can be divided into the gray cast iron pipe and the ductile iron pipe based on the material. Connection types of cast iron pipes can be classified into flexible connections and flanged connections according to connection modes. Flexible cast iron pipes adopt rubber seals; we use flanges to fix flanged cast iron pipes and rubber flange gaskets to seal flanges. 

Cast iron pipes can be divided into gray iron pipes, ductile iron pipes and high-silicon iron pipes according to their different materials.

A simple introduction to different cast iron pipes
1. Cast iron pipes for water supply
Cast iron pipes for water supply are made from cast molten iron after cast molten iron being added spheroidizing agents and processed by centrifugal ductile iron machines with high-speed centrifugal casting.

The ductile iron pipe has essence of iron, performance of steel, good ductility, easy installation, excellent corrosion resistance and good sealing performance, and it is mainly applied to water, gas and oil transportation for municipal administration and industrial and mining enterprises. The ductile iron pipe is the first choice for the water supply pipe and is cost-effective. 

Nominal diameters of ductile iron pipes are from 80 to 2200 millimeters and lengths of ductile iron pipes are 5 meters, 6 meters and 8 meters. Compared with gray cast iron pipes, ductile iron pipes have advantages of high strength, good toughness, thin walls, using less amount of metal and being able to bear high pressure. 

2. Sand spun cast iron straight pipes
Materials of sand spun cast iron straight pipes are gray cast iron, and sand spun cast iron straight pipes are used for transporting pressure fluids such as water and gases. 

3. Continuous cast iron straight pipes
Continuous cast iron straight pipes are gray cast iron pipes that are made by continuous casting processes, which are applied to transporting pressure fluids such as water and gases. 
 
4. Cast iron pipes for drainage 
Cast iron pipes for drainage include ordinary socket cast iron pipes and pipe fittings. Flexible anti-seismic interface cast iron pipes adopt rubber seals and are fixed by bolts, which have flexibility and elasticity under internal water pressure. Flexible anti-seismic interface cast iron pipes can be used as high-rise buildings’ indoor drain pipes, which are especially suitable for earthquake areas.